The leading edge region of a turbine airfoil is subjected to some of the highest head loads when an engine is operating. To protect the airfoil from damage, cooling air may be directed in and/or onto the airfoil. Cooling provided by a combination of impingement jets and film cooling air can prevent thermal damages to the airfoils.
One issue with cooling known airfoil assemblies, however, is that an excessive quantity of coolant is required to sufficiently cool the leading edge of the turbine airfoils. Additionally, due to geometric constraints of the leading edge of the airfoil, there are limited strategies for cooling the leading edge of the airfoil as well as downstream from the leading edge. Such an improved system may provide improved cooling of critical portions of the turbine assembly, enable more efficient operation of the engine, and improve the life of the turbine machinery. This can be achieved through increases in the firing temperature, reductions in the cooling flow, or a combination.